Paintings by postwar abstract artist Mark Rothko are highly coveted — in May one of his works sold at auction in London for $50 million. But oddly enough, Harvard University has had a handful of Rothkos — faded by sunlight and splattered with food and drink — in storage. Now, new technology has led to a potentially controversial restoration.

Retired Harvard curator and conservator Marjorie Cohn was an apprentice at the Harvard Art Museums around the time Rothko was commissioned to create wall-sized paintings for a new space at the university's Holyoke Center. When the painter arrived with his finished, rolled-up canvases in 1963, Cohn remembers the entire conservation department showed up to stretch the huge plum and crimson-colored paintings onto wooden frames.

"The atmosphere then was so positive," she recalls. "He had nothing but praise for our efforts in getting things ready for him, and we of course were just thrilled to be working with such a famous artist."

Rothko took no money for the five paintings, but he did demand that they always be hung as a group in a penthouse dining room, with the drapes drawn.

"My boss was on the telephone all the time ... about making sure those curtains were kept closed," Cohn says. "But of course they weren't. It had the best view in Cambridge. Everybody went there for parties. They could care less about Rothko murals. They were there for a party, and they opened the curtain to look at the view, and you really can't blame them."

Rothko died in 1970. His Harvard paintings eventually became so damaged by sunlight — and splattered with cocktails and food — that the university took them down in 1979 and put them in storage. They've been displayed just twice in the U.S. since then. Some at Harvard blamed the artist for insisting they be hung in a busy dining room. His son, Christopher, says the family was furious.

"We were upset that they had so thoroughly misunderstood my father's intentions and thought that he didn't even care about his own work," he says. "Nothing could have been further from the truth."

But now the Rothko family has partnered with the Harvard Art Museums to revive the five legendary works. The process began with a sixth painting created at the same time that went home with Rothko in the '60s. It stayed rolled up, safe from booze and light damage. With access to that, the conservators had a benchmark for the original colors. But they couldn't duplicate them, says conservator Jens Stenger, who collaborated on the restoration.

"Rothko made his own paint," Stenger says. "He used animal glue, and he heated it up and poured in dry pigment. He also used whole egg as a binding medium to disperse the pigment."

In fact Rothko kept his recipe so secret he didn't even tell his assistants. Stenger says the concoction actually penetrated the canvas. "It's like a stain. If you would start in-painting this you would completely remove the artist's hand; you would remove the brushwork."

"In-painting" is one of the traditional methods of restoring artworks: Conservators repaint over damaged areas, matching as best they can. Since that wasn't possible with the Rothkos, they had to come up with a different approach.

"What we're doing is using light as a retouching tool," says Narayan Khandekar, senior conservation scientist at the Harvard Art Museums. "In the same way that when you restore a painting, traditionally you use paint to restore the lost colors. In this case we're using light to fill in those missing areas."

Each of Rothko's faded murals is illuminated by a projector suspended from the ceiling. It took years for the team to develop this new technique, and they're still tweaking it with help from the MIT Media Lab's Camera Culture group and Swiss researchers. The projectors and their software shine light on the canvases in incremental degrees, correcting where needed, says Carol Mancusi-Ungaro, who directs Harvard's Center for the Technical Study of Modern Art.

"This system enables us to color correct, pixel by pixel, specific areas, without flooding the entire painting with a colored light," Mancusi-Ungaro explains. "But it also enables us to do it without physically touching the painting."

Mancusi-Ungaro restored faded paintings the old-fashioned way at Rothko Chapel in Houston. She expects skeptics to chime in when the Harvard murals are unveiled officially in the fall. Art critics are not allowed to see them until then — but the museum has heard from perhaps the toughest reviewer: Rothko's son, Christopher, saw his father's murals after their illuminated restoration.

"I got the goose bumps!" Rothko says. "I was really struck right away not so much by the color but by the way they still felt like paintings. Because it's just projecting a transparent light on there, you still have the feel of the canvas. For me that's what makes it still feel so believable. Because, you know, my father's brush strokes are still there."

Artwork worth millions of dollars is set to make a campus comeback. Abstract artist Mark Rothko created five monumental paintings for Harvard University back in the 1960s, but by the '70s, they'd been virtually trashed. Now a team of curators and scientists has pioneered technology to restore the ruined Rothkos, and without a drop of paint. Very few people have actually seen the restored paintings. Andrea Shea of member station WBUR is one of them, and she sends this report.

ANDREA SHEA, BYLINE: In May, a Rothko sold at auction in London for $50 million.

MARJORIE COHN: Everybody wants a Rothko, and the fact that Harvard has a whole room of them that nobody sees is the other side of the story.

SHEA: Retired Harvard curator and conservator Marjorie Cohn was an apprentice at the Harvard art museums around the time Mark Rothko was commissioned to create wall-sized paintings for a new space at the university's Holyoke Center. When the painter arrived with his finished, rolled up canvases in 1963, Cohn remembers the entire conservation department showed up to stretch the huge plum and crimson colored paintings onto wooden frames.

COHN: The atmosphere, then, was so positive. He had nothing but praise for our efforts in getting things ready for him, and we, of course, were just thrilled to be working with a famous artist.

SHEA: Rothko took no money for the paintings, but he did demand that they always be hung as a group in a penthouse dining room with the drapes drawn.

COHN: And my boss was on the telephone all the time to the manager of the space about making sure those curtains were kept closed, but of course they weren't. It had the best view in Cambridge. I mean, everybody went there for parties. They could care less about Rothko murals, and they opened the curtains to look at the view. And you really can't blame them.

SHEA: Mark Rothko died in 1970. His Harvard paintings eventually became so damaged by sunlight and splattered with cocktails and food, that the University took them down in '79 and put them in storage. They've been displayed just twice in the U.S. since then. Some at Harvard blame the artist for insisting they be hung in a busy dining room. His son, Christopher, says the family was furious.

MARK ROTHKO: We were upset that they had so thoroughly misunderstood my father's intentions and thought that he didn't even care about his own work, which - nothing could've been further from the truth.

SHEA: But now, the Rothko family has partnered with the Harvard art museums to revive the five legendary works. The process began with a sixth painting, created at the same time, that went home with Rothko in the '60s. It stayed rolled up, safe from booze and light damage. With access to that, the conservators had a benchmark for the original colors, but they couldn't duplicate them says former Harvard conservator, Jens Stenger, who's now at Yale and who collaborated on the restoration.

JENS STENGER: Rothko made his own paint. He used animal glue, and he heated it up, and he poured in dry pigments. He also used whole egg as a binding medium to disperse pigment.

SHEA: In fact, Rothko kept his recipe so secret, he didn't even tell his assistants. Stenger says the concoction actually penetrated the canvas.

STENGER: It's like a stain. If you would start inpainting this, you would completely remove the artist's hand. You would remove the brush work.

SHEA: Inpainting is one of the traditional methods of restoring artworks. Conservators repaint over damaged areas, matching as best they can. Since that wasn't possible with the Rothkos, they had to come up with a different approach.

NARAYAN KHANDEKAR: What we're doing is using light as a retouching tool.

KHANDEKAR: In the same way that when you restore a painting, traditionally you use paint to restore the lost colors. In this case, we're using light to fill in those missing areas.

SHEA: Each of Rothko's faded murals is illuminated by a projector suspended from the ceiling. It took years for the team to develop this new technique, and they're still tweaking it with help from the MIT media labs camera culture group and Swiss researchers. The projectors and their software shine light on the canvas in incremental degrees, correcting where needed, says Carol Mancusi-Ungaro. She directs Harvard's center for technical studies of modern art.

CAROL MANCUSI-UNGARO: This system enables us to color correct pixel by pixel, specific areas without flooding the entire painting with a colored line. But it also enables us to do it without actually physically touching the painting.

SHEA: Mancusi-Ungaro restored faded paintings the old-fashioned way at Rothko Chapel in Houston. She expects skeptics to chime in when the Harvard murals are unveiled officially in the fall. Art critics are not allowed to see them until then, but the museum has heard from perhaps the toughest reviewer. Rothko's son Christopher saw his father's murals after the illuminated restoration.

ROTHKO: I got the goosebumps. I was really struck right away, not so much by the color, but by the way they still felt like paintings. Because it's just projecting a transparent light on there, you still have the feel of a canvas. For me, that's what makes it still feel so believable because, you know, my father's brushstrokes are still there.

SHEA: And the bloody Marys and hors d'oeuvres are gone. For NPR News, I'm Andrea Shea in Boston.

BLOCK: You're listening to ALL THINGS CONSIDERED from NPR News. Transcript provided by NPR, Copyright NPR.